Das Internet of Things lässt sich Systemtechnisch in drei Bereiche einteilen: Constrained Devices, Gateways und Cloud Platforms. Im Bereich der Cloud hat Java ein Heimspiel. Und auf constrained Devices ist Java immer noch eher eine Randerscheinung. Doch auf dem Verbindungsstück, dem IoT Gateway, kann Java all seine Stärken ausspielen. In diesem Vortrag wird gezeigt, wie man als Java-Entwickler mit ein paar Eclipse IoT Projekten und einem Raspberry Pi ein IoT Gateway prototypisieren kann. Es werden dabei auch nicht-Java-Themen wie zum Beispiel Sensorik und General Purpose Input Output (GPIO) gestreift. Zur Veranschaulichung wird ein für Demonstrationszwecke selbstgebautes, smartes Mini-Gewächshaus mitgebracht, in dem einige Sensoren und Aktoren verbaut sind und dessen Software mit Java entwickelt ist.

1. Generative Software GmbH
Java User Group Freiburg
5. März 2018
Internet of Things für Java-Entwickler
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2. Agenda
 What is IoT?
 IoT Gateway with Eclipse IoT
 The Story of the Smart Greenhouse
 Live-Demo of the Smart Greenhouse
 The Architecture of an IoT Gateway
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3. What is IoT?
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4. Goals of IoT Solutions
 Transparency – what is going on?
 Traceability – what was going on?
 Prediction – what will be going on?
 Emergency – what is badly wrong?
 Optimization – what to do to improve processes?
 Agility – what intervention makes sense?
 Automation – what can be done by machines?
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5. Sensor Categories
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Gateway, Server, Cloud
Passive
Active – Always On
Active – Wake Up
Gateway, Server, Cloud
Gateway, Server, Cloud
Microprocessor

6. Where to use Sensor Data
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Time Frame On Device (Edge) On Stream (Fog) In Batch (Cloud)
Hours to Weeks In Database
Strategic Insight
Machine Learning
Minutes to Hours In Process
Performance Insights
Summary Statistics
Seconds to Minutes Operational Insight
Rules Engine
Microseconds to Seconds Signal Processing
IoT Gateway

7. Protocols
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HTTP CoAP AMQP XMPP MQTT
Architecture Request/Response Request/Response Point-to-Point
Publish/Subscribe
Request/Response
Publish/Subscribe
Publish/Subscribe
Representation Text, Binary Binary Binary Text Binary
Transport TCP UDP TCP TCP TCP
Security (Transp.) TLS DTLS TLS TLS TLS
Discovery No Yes No No No
Scope Device-to-Cloud Device-to-Device Device-to-Cloud
Cloud-to-Device
Device-to-Cloud
Cloud-to-Device
Device-to-Cloud
Cloud-to-Device
Suitable for
Constr. Devices
Possibly Yes Possibly Possibly Yes
Server Updates Pull Pull, Push Push Push Push

8. Networks
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Data Unit OSI Layer Examples
Host/Service
Layers
Data Application HTTP, FTP, ‚IoT Protocols‘ Peer-to-Peer
Protocols
Presentation TLS, SSL
Session NetBIOS
Segment/Datagram Transport TCP, UDP
Network
Protocols
Device/Media
Layers
Packet/Datagram Network IP, ARP, ICMP, IPSec
Frame Data Link Ethernet, ATM, PPP
Bit Physical Ethernet, WiFi, USB, Bluetooth, SPI, I2C

9. Eclipse IoT
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 Working Group
– Members: 39 (Mar 2018), RedHat, SAP, Intel, Bosch, Canonical,
Cloudera, DB Systel, Huawei, IBM, Siemens, Sierra Wireless, …
– Community: IoT Testbeds, Youtube, Meetups, Whitepapers,
Surveys, Conferences, Open IoT Challenge …
 Technology
– Eclipse Projects: Paho, Kura, Californium, Mosquitto, Vorto, Milo,
Kapua, Hono, HawkBit, …
– Standards: CoAP, MQTT, OPC UA, OMA LWM2M, …
– Programming Languages: Java, C, C++, Python, …

10. OSGi
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 Originally: Open Services Gateway initiative
 Today: OSGi Alliance (defines APIs and Test Cases)
 Open, modular and scalable „Service Delivery Platform“
 Java-based
 Well-known Open Source Frameworks:
– Knoplerfish
– Eclipse Equinox
– Apache Felix
– Concierge
 Modularization with so-called „Bundles“
 Visibility of Java Packages
 Semantic Versioning of Java Packages
 (Declarative) Services

11. Smart, Smarter, …
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12. Requirements for the IoT Greenhouse
 Show all Sensor Values on a Display
 Control Plant Lamp depending on Luminocity
 Control Water Pump depending on Soil Humidity
 Control Heating depending on Air Temperature
 Switch on a Buzzer when Gas Sensor detects Gas
 Send Sensor Data to a Server and store it there
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13. Buy an IKEA Mini Greenhouse …
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14. … assemble it …
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15. … fill it with Hardware …
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16. … add Software to it …
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17. … connect it with a Network …
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18. … and ready is the Smart Greenhouse

19. Software Stack
Eclipse IoT
 Kura (IoT Gateway Software, Java+OSGi)
 Mosquitto (MQTT Broker)
 Paho (MQTT Client)
 Californium (CoAP)
Jakarta EE
 JAX-RS
 JAXB
 JSF
 Servlets
 EJB
 JPA
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20. The Smart Greenhouse - Details
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IoT Gateway (Raspberry Pi 2)
Kura, Paho, Californium
IoT Server
Paho, Californium
Glassfish 4.1
Java EE
Network Connection
Sensors
MQTT Broker
Mosquitto
Actuator „LED Strip“
Hose to Actuator „Pump“
LCD Display

21. What shall the IoT Solution do?
1. Read Sensors with the Kura IoT Gateway
2. Execute Business Logic with the Kura IoT Gateway
3. Send Sensor Data to Mosquitto with Paho (MQTT)
4. Collect Sensor Data with Paho and Servlets
5. Persist Sensor Data by Means of a REST API (JAX-RS, EJB, JPA)
6. Display Sensor Data by Means of a JSF Web App (uses same REST-API)
7. Control Actuators with a JSF Web App and Californium (CoAP)
8. Execute Business Logic on a Server with Paho and EJBs
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22. Live Demo!
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23. MQTT
(Message Queue Telemetry Transport)
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Message
Broker
Publisher Subscriber
publish to …
client-id/app-id/temperature
subscribe to …
client-id/app-id/temperature
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SubscriberPublisher

24. MQTT
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 [account-name]/[client-id]/[app-id]/[resource-id]
 Subscription Wildcards
# … e.g. client-id/app-id/#
client-id/app-id/temperature
client-id/app-id/plant/light
client-id/app-id/plant/moisture
+ … e.g. client-id/app-id/+/light
client-id/app-id/plant/light
 Do not subscribe to # (all messages)

25. CoAP
(Constrained Application Protocol)
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CoAP
Server
CoAP
Client
GET request: coap://<CoAP-Host>:5683/temperature
response
GET
PUT
POST
DELETE
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2
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26. OSGi Container
Eclipse Kura
Paho
CoAP
OpenJDK I/O
Californium
…
Paho
Publisher
Device Service
Simulation
MQTT
Service Interfaces
Legende
Service-Aufrufe
Data Flow
OSGi Bundle
Simulationsdaten
Sensordaten simulieren
und verschicken
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27. OSGi Container
Eclipse Kura
Paho
CoAP
OpenJDK I/O
Californium
…
Paho
Publisher
Business Logic
Device Service
Simulation
MQTT
Service Interfaces
Legende
Service-Aufrufe
Data Flow
OSGi Bundle
Simulationsdaten
Gateway-Logik
simulieren
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28. Device Access with Java
 OpenJDK Device I/O: GPIO, I2C, UART, SPI
 TinyB: Bluetooth LE
 Pi4J: Object-Oriented API to access I/O
Capabilities of Raspberry Pi
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29. Kura
Eclipse Kura
Paho
CoAP
OpenJDK I/O
Californium
…
Kura
Data Service
Device Service
MQTT
Service Interfaces
Legende
Service-Aufrufe
Data Flow
OSGi Bundle
Echte Sensordaten
verschicken
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30. Kura
Eclipse Kura
Paho
CoAP
OpenJDK I/O
Californium
…
Kura
Data Service
Business Logic
Device Service
MQTT
Service Interfaces
Legende
Service-Aufrufe
Data Flow
OSGi Bundle
Gateway-Logik
implementieren
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31. Tutorials on Github and Bitbucket
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Eclipse Tutorial: github.com/kartben/kura-greenhouse-demo
Greenhouse Tutorial: bitbucket.org/jenerateit/tutorial-smart-greenhouse
Tutorial IOTDEV-Kurs: bitbucket.org/jenerateit/tutorial-smart-production-monitoring

32. Thank you!
 Summary
 Questions
 Outlook
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Marcus Munzert
CEO and President
munzert@generative-software.com
Generative Software GmbH
Cornelia-Schlosser-Allee 15
79111 Freiburg
Germany
www.generative-software.de
www.virtual-developer.com